Roller finger followers are valve train components which translate motion between a camshaft and a valve stem. Many roller finger followers include a roller mounted in a housing by an axle. In some instances, the axle is fixed to the housing, such as through a staking operation. One drawback of this configuration is that roller finger followers with fixed axles may experience uneven wear. For instance, more wear generally occurs on the axle at a location of highest loading or which experiences the most contact.
In order to help promote even wear distribution, some roller finger followers employ a “floating” axle. A floating axle is configured to rotate relative to the housing. The rotation changes the position of the axle during the life of the component, thereby directing wear to occur at different points around the supported periphery of the axle and promoting a more even wear distribution. Examples of floating axles are featured in U.S. Pat. Nos. 7,712,443 and 8,328,959 (“the '959 Patent”).
In some configurations, such as that shown in the '959 Patent, a floating axle may be configured to rotate simply by placing the ends of the axle in holes in the housing and enlarging the ends of the axle to ensure that the axle does not slide axially out of the holes. However, several factors may lead to axles with this configuration not actually rotating during use. For example, the holes in the housing or the axle may be out-of-round or may include a high surface roughness which causes friction and inhibits or prevents relative rotation. In these situations, the axle does not rotate or gets stuck in a particular angular position, effectively producing a fixed axle which is susceptible to the uneven wear problem.
The present disclosure is directed to overcoming these and other problems of the prior art.